That's what they say. Devil Fruits are so rare that its unlikely he'd find another one anyway.
Having a doctor aboard a ship is extremely necessary, I'd say. Especially for this crew.
You know, now that I think about it, I haven't met anyone in my dreamworld that is anything close to a lawyer. The towns and kingdoms seem to govern themselves, but I think the World Government holds supreme power and authority over everyone. The marines seem to be the only real police force I've seen so far. It's a little...unsettling.